1. Field of the Invention
The invention is primarily directed to a technique for the no-contact printing of carpet, and more particularly, to a no-contact printing technique that uses sublimable dyes on a transfer carrier and a spacer-transfer device between the transfer carrier and the carpet being printed to dye the fibers of the carpet.
2. Description of the Prior Art
U.S. Pat. No. 3,458,335 teaches a heat sensitive transfer sheet having an open screen layer thereon and the method of making this sheet. An open, fine screen layer having strips ranging in height from between 0.00001 inch and 0.01 inch and being uniformly spaced from each other by a distance in the range of between 0.00001 inch and no more than about 0.05 inch is provided over a coating of heat vaporizable or sublimable material on a transfer sheet. The open, fine screen layer is used to prevent the contact-migration of the vaporizable material on the transfer sheet when a copy sheet is placed in contact with the transfer sheet when no heat is being applied to the transfer sheet, and especially, when the transfer sheet is stored in contact with a copy sheet for a prolonged period of time.
The inventive technique herein uses a honeycomb structure with passageways therethrough as its spacer-transfer device to space the transfer sheet from the carpet being printed and to produce and maintain laminar flow of the sublimed dyes between the transfer sheet and the carpet being printed. The prior art teaches the use of the open, fine screen layer to prevent the transfer of sublimable material to a copy sheet when in contact with the copy sheet and prior to heating the sublimable material.
U.S. Pat. No. 2,984,540 teaches a method and apparatus for printing and dyeing pile carpeting. A large number of small, contiguous color receptacles formed by thin, upstanding rubber walls are formed on the surface of an endless belt. The individual color receptacles are filled to a desired level with a coloring agent or material. The pile of the carpet is pressed into the color receptacles as the carpet is pressed against the rotating endless belt having the color receptacles thereon. The pile is thereby dyed. The walls of the color receptacles prevent any lateral shift back squeezing of the coloring agent, resulting in an even, uniform coloring action and a perfect consistency and uniformity of fabric color regardless of the length of the run.
The inventive technique herein uses sublimable dyes for the printing, whereas this prior art teaches the use of a viscous coloring agent applied directly to the pile for the printing of the carpet. Also, the inventive technique herein does not require the use of any mechanical pressure to transfer the sublimable dyes to the carpet, whereas this prior art teaches the necessity of using such mechanical pressure. Lastly, the inventive technique herein uses any one of the passageways of the spacer-transfer device to transfer one or more colors therethrough from the transfer sheet to the carpet being printed, whereas this prior art teaches the use of transferring to the carpet from the color receptacle one color for any one color receptacle.
U.S. patent application Ser. No. 612,908, which has the same assignee as this application, teaches the printing of a carpet using sublimable dyes. A pattern is placed on a porous transfer sheet by the use of sublimable dyes. The side of the transfer paper printed with the sublimable dyes is placed adjacent the face yarns of the carpet. Heated air passing through the porous transfer sheet and the carpet causes the dyes to sublime and move from the transfer sheet to the face yarns of the carpet, thereby dyeing these face yarns.
This prior art application teaches that a shart, well-defined image is formed on the face fiber yarns of the carpet when the transfer sheet contacts the yarns and that at about a 1/8 inch (0.3 cm) spacing between the transfer sheet and the face fiber yarns, a slight change in sharpness of image is noted and that at 1 inch (2.5 cm) spacing between the transfer sheet and the face fiber yarns, the printed image on the face fiber yarns is diffused. The applicants' invention teaches a method of transfer printing which uses a spacer-transfer device between the transfer sheet and the carpet being printed to achieve greater spacing therebetween than was possible with this prior art while still maintaining a sharp image transfer.